Passenger railroad cars are supported on wheeled trucks located beneath opposite ends of each cars. Each truck includes at least two pairs of wheels with each wheel pair being respectively interconnected with an axle at opposite ends thereof. A separate disc brake assembly and a separate tread brake assembly is mounted to the truck adjacent to each wheel in a well-known manner to impart a braking force to slow or stop the train.
Both the disc and the tread brakes utilize brake actuator units which are air actuated to extend piston and cylinder controlled disc and tread brake components into braking contact with the axle and wheels, respectively. The brake units also each include a slack adjuster mechanism that automatically adjusts the position of the brake components to account for wear during use. Examples of such disc and tread brakes used in railway cars are the Knorr PR-5 Amfleet 1 tread brake; the Knorr CK-8Z Amfleet 1 disc brake; the Wabco 3-P Amfleet 2 disc brake; and the Wabco GB-41/2 Amfleet 2 tread brake.
The aforesaid brake assemblies are pressure tested frequently (e.g. daily) to ensure operability. If an assembly fails, it is immediately replaced and returned to a back shop, overhaul environment for overhaul and retesting. In addition, at less frequent intervals (e.g. every 3-4 years) as mandated by appropriate association of governmental control (e.g. the Association of American Railroads and the Federal Railroad Administration), the passenger coach cars are overhauled in the back shop environment, where all of the car components are replaced with new or reconditioned components.
During the overhaul process, in the past, each of the individual types of tread and disc brakes were disassembled into component parts, the components then cleaned, inspected, reconditioned or replaced, and then reassembled into rebuilt brake actuator units. The original rebuild process used by the Assignee of the present invention included up to four separate disassembly-cleaning-inspection-reassembly lines, one for each of the four above identified actuator units, each line being staffed with its own group of workers. Needless to say, this prior art process was disadvantageously labor and equipment intensive.
The brake actuators subject to reconditioning are large and heavy pieces of equipment. In the prior art processes noted above, significant physical exertion by workers was necessary to manually lift and move the actuators from one work area to another work area. In addition, in the disc brake actuator disassembly areas, difficulty was encountered in the removal of certain subassemblies in which either a large spring force must be relieved to facilitate removal of certain fasteners, or in which the threaded connection between certain threaded components `froze` and locked, as a result of enormous torque forces imposed on the threaded connection during years of use of the brake actuators in the railway car trucks. In the past, for example, large chain wrenches were used in the disc brake subassembly areas to disassemble a piston sleeve housing which could potentially subject the worker to injury if the large chain wrench (e.g. 3'-4' in length) slipped from the relatively small bearing surface on the sleeve.
It is accordingly one object of the present invention to disassemble, inspect and rebuild multiple types of brake actuator units in a single conveyorized line.
Another object is to utilize the same work crew in each of the disassembly, inspection, and reassembly areas for each of the different types of brake actuator units being rebuilt.
Yet another object is to provide ergonomically safe areas to minimize excessive manual exertion and heavy lifting by the workers.
Yet another object is to provide novel types of apparatus to facilitate breakdown of large and heavy threaded components and subassemblies including spring biased components.